Video on demand (VoD), audio on demand and other streaming data transfer applications are emerging technologies for home entertainment service businesses. For example, a VoD service permits a customer to request a video in real-time from a large collection of videos stored on a server located in a remote facility. Video transfer can be provided over a network system, such as a telephone system or a cable network, for example. A sufficient amount of bandwidth must be available however to continuously transfer the data from the storage system to the customer's equipment. The amount of bandwidth between a video server and the customer's equipment ultimately determines the maximum number of simultaneous video streams the server can support at any given time.
One key communication transmission technology that is enabling transformation of existing public information networks to accommodate higher bandwidth needs is Asymmetric Digital Subscriber Line (ADSL), a modem technology. ADSL converts existing twisted-pair telephone lines into access paths for multimedia and high-speed data communications. ADSL rates expand existing access capacity by a factor of, say, 50 or more without new cable installations.
Asymmetric Digital Subscriber Line ADSL technology involves modems attached across twisted pair copper wiring in which higher transmission rates can be achieved. When transferring data over these twisted pairs, it is possible that the DSL modem physical layer will lose synchronization due to changing line conditions. These line conditions can be dependent upon impulse noises, and other nearby sources of interference. It is also possible that this loss of synchronization can occur during a period of time when a customer is watching a program (e.g., a pay-per-view service such as Video on Demand (VoD)). If the modem were to lose synchronization and a re-synchronization is attempted, the customer loses a portion of the streaming data and the video, audio, etc. is interrupted or even terminated. If the DSL modem loses physical layer synchronization, the video or data stream can no longer be sent across the network from a video server to a customer and an interruption of service results.
Therefore, a need exists for a system and a method that prevents interruption of a data stream when a DSL modem loses physical layer synchronization.